Field of the Invention
The present invention relates to a decorative member for vehicle, decorative member which is used for electromagnetic-wave transmission covers disposed in front of millimeter-electromagnetic-wave radar, for instance.
Description of the Related Art
Auto-cruising systems are an engineering technique for controlling inter-vehicular distance, or distance between two vehicles. An auto-cruising system comprises an onboard sensor that a vehicle has on the front side. The onboard sensor measures inter-vehicular distances between a trailing vehicle (or one's own vehicle) and a leading vehicle, or relative speeds of the trailing vehicle's speeds to the leading vehicle's speeds. Based on the resulting information, the auto-cruising system controls the throttle or brake of one's own vehicle in order to accelerate or decelerate one's own vehicle, thereby controlling the inter-vehicular distances. As an onboard sensor that is employed for auto-cruising system, laser radars, or millimeter-electromagnetic-wave radars have been used commonly. A millimeter-electromagnetic-wave radar transmits a millimeter electromagnetic wave, and then receives the millimeter electromagnetic wave that has collided with and has reflected from an object. Thus, the millimeter-electromagnetic-wave radar measures inter-vehicular distances or relative speeds between a leading vehicle and a trailing vehicle (or one's own vehicle) based on differences between the resultant transmitted electromagnetic wave and received electromagnetic wave. For example, the transmitted millimeter electromagnetic wave exhibits a frequency of from 30 GHz to 300 GHz, and exhibits a wavelength of from 1 mm to 10 mm. Moreover, an electromagnetic-wave transmission cove is disposed in front of the millimeter-electromagnetic-wave radar. That is, the millimeter electromagnetic wave, which the millimeter-electromagnetic-wave radar has irradiated or emitted, is transmitted through the electromagnetic-wave transmission cover, and is then outputted forward ahead of a trailing vehicle (or one's own vehicle).
As illustrated in FIG. 16, a conventional electromagnetic-wave transmission cover comprises a transparent base 92, a decorative layer 93, a metallic layer 95, and a base layer 96, for instance. The transparent base 92 covers the decorative layer 93 on the front side. The base layer 96 retains the metallic layer 95 on the rear side. The transparent base 92 is provided with a recessed section 921 and an ordinary section 920 in the rear face. The decorative layer 93 covers the ordinary section 920, that is, sections other than the recessed section 921, while leaving the recessed section 921 uncovered. The metallic layer 95 covers the recessed section 921 in the rear face of the transparent base 92. When the conventional electromagnetic-wave transmission cover is viewed on the front side, the metallic layer 95 formed on the recessed section 921 appears through the transparent base 92 as if it stands out up forward (or as if it is embossed therein in relief). The decorative layer 93 appears down below in the ordinary section 920 around the recessed section 921 of the transparent base 92.
As a method for forming such a decorative layer, Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2012-111045 discloses a hot stamping (or pressing) method that has been heretofore available conventionally. In the disclosed method, a stamped foil 97 with a decorative layer 93 provided is pressed onto a transfer face 92a of a transparent base 92 while heating the stamped foil 97 with use of a stamping jig 91 having a built-in heater coil 91a, as shown in FIGS. 17 and 18 accompanied herewith. Note that FIGS. 17 and 18 correspond to FIGS. 4(b) and (c) in Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2012-111045. Moreover, the heating/pressing step is carried out after putting all of the stamping jig 91, the transparent base 92 and the stamped foil 97 in a case 94 and then depressurizing the atmosphere within the case 94. After completing the heating/pressing step, the case 94 is opened to put the inner atmosphere back to the atmospheric pressure, and then the stamping jig 91 is separated from the stamped foil 97. Since the stamped foil 97 covers recessed sections 921 in the transparent base 92, the depressurized state prior to opening the case 94 can be kept inside the recessed sections 921. Consequently, the decorative layer 93 comprising the stamped foil 97 can be formed on ordinary sections 920 around the recessed sections 921 in the transparent base 92. After the stamped foil 97 has been taken off from the transparent base 92 except for the decorative layer 93 formed on the ordinary sections 920, the metallic layer 95 is formed on the rear face of the transparent base 92 with which the decorative layer 93 has been provided.
However, the conventional decorative layer 93 formed by the above-described hot stamping method has been associated with room or need for improving the looks, because it appears flat when being viewed through the transparent base 92. Moreover, not only conventional electromagnetic-wave transmission covers, but also conventional emblems having the same construction as that of the conventional electromagnetic-wave transmission covers have also been associated with room or need for improving the looks when the conventional emblems are provided with a decorative layer by the hot stamping method.